A fertile patient with 45X/47XXX mosaicism: Turner syndrome (TS) is a sex chromosome abnormality with a frequency of 1/2,000-3,000 among female live births. Characteristic findings are short stature and gonadal dysgenesis. Short and webbed neck, low posterior hairline, broad chest, widespread nipples, cubitus valgus, short 4th and 5th metacarpals, multiple pigmented nevi, primary amenorrhea, lack of secondary sexual characteristics, cardiovascular and renal anomalies are the most common presentations. Most of the cases are infertile. Spontaneous pregnancy is unusual and the risk for congenital anomaly, spontaneous abortion, stillbirth and aneuploidy is increased. Fifty percent of the patients have classical monosomy X (45,X). However mosaicism of 45,X/47,XXX is rare and accounts for 1.7% of the TS cases. Some cases may not reflect the characteristic phenotype. Some cases with normal height, normal menstrual cyclus and fertility have been defined before. The case we present herein is a 26 years old woman who was admitted to our clinic due to recurrent pregnancy loss. In her medical history she had type 1 diabetes mellitus and endometrium cancer, in her family history her mother had recurrent pregnancy loss. The patient's first, third, fourth, fifth and sixth pregnancies had resulted in spontaneous abortions in the first trimester. She had a healthy daughter with 46,XX karyotype from her second pregnancy. A 45,X/47,XXX karyotype was detected by conventional cytogenetic analysis of the patient who did not have dysmorphic findings. The mosaicism was confirmed by FISH analysis with CEP X probe. Of the 100 cells evaluated, 65 of them had 3 signals of X chromosome while 35 had 1 signal. We present the case because of its scarcity in the literature.